Physical therapists commonly treat patients with Parkinson's disease. Typical clinical interventions used by physical therapists including strengthening, stretching and aerobic training have been shown to improve function and quality of life of persons with Parkinson's disease. Alternative exercise interventions that incorporate non-traditional concepts, such as tango dance, tai chi and taiji have also been found to lead to improvements in function in persons with Parkinson's disease. It is important that comparisons between different types of exercise programs for persons with Parkinson's disease be explored in order to determine effective options for care.